As you say but A get 4 dice in melee. They don't get overlaps, but they have two front rank bases who are not overlaps, and two bases behind them
Let's discuss this a minute. I agree that 2 bases of A appear to be in contact with green. The 'good' book says (and I now quote scripture, chapter and verse) : "- Fights in any direction with one quarter of its bases, rounded up. Half of these, rounded up, count as front rank bases." So it has 8 total bases and 1 front and 1 rear rank fighting in each direction. If you fight a column with A you get 6 dice in melee, 2 for head to head and 4 for overlaps. Why is this any different? The orb is a special all round defensive formation. For purposes of simplifying playing the game it is depicted as 2 wide with half the ranks facing to the rear (
probably looking out for philqw78). In fact per the 'good' book an 8 stand BG in orb only has 1 front base facing in each direction that can't be overlapped. The appearance of A having 2 bases in contact is irrelevant.
Therefore, whereas and wherefore, in so far as, considering the facts of the matter, and just plain because; I submit to this esteemed body that the correct dice for A in melee is 2.
P.S.
berthier has the correct answer, so he gets to wear the PJs. Brace yourself, berthier.